The present invention relates to an air-liquid separating chamber for separating a liquid containing bubbles into air and liquid, and an ink jet printer provided with the same, in particular, relates to an air-liquid separating chamber for introducing an air-liquid mixture, such as a waste ink from an air-liquid introducing inlet port on the upper surface side into a main body accommodating a member for promoting separation so as to be separated into liquid and air, discharging the separated air to the outside from a gas discharging outlet port on the upper surface side, and discharging the separated liquid to the outside from a liquid discharging outlet port on the lower surface side, and an ink jet printer provided with the same.
Air-liquid separating chambers for separating an air-liquid mixture into liquid and gas are used in various technical fields. Naturally, as to the performance of the air-liquid separating chamber, an air-liquid separating chamber having a high separation property (separation efficiency), capable of providing a liquid after separation without a gas, that is, bubbles remained (mixed) and a gas after separation without a liquid remained (mixed) is regarded to be preferable.
For example, in an ink jet printer (for example, Jpn. Pat. Appln. KOKAI Publication No. 10-138520) comprising a large number (for example, 1,000 pieces) of ink jet nozzles arranged in the main scanning direction (a direction of width of a paper sheet), capable of printing one line simultaneously on the paper sheet by driving all the ink jet nozzles at the same time, and as a result, capable of printing 600 or more paper sheets at 20 PPM with a high image quality with colors continuously, maintenance for preventing choking of each ink jet nozzle is important. According to the trend toward the high performance of the ink jet printer, it is required to treat the waste ink discharged from each ink jet nozzle certainly, and achievement of efficiency in separating into a gas and a liquid is required.
FIG. 1 is a schematic block diagram showing an ink jet nozzle head of an ink jet printer having an air-liquid separating chamber and a maintenance part for preventing choking of the ink jet nozzle. In FIG. 1, a nozzle head 10 for one color is illustrated. The nozzle head 10 has an ink room 11, with the ink room 11 communicating with an ink jet nozzle 12. At the time of maintenance, each ink jet nozzle 12 is faced to an ink receiving member 21 so that an ink is forcibly pressed in this state so as to be supplied into the ink room 11 and the ink (liquid) discharged from each ink jet nozzle 12 is received by an ink receptacle 22. Thereafter, the ink receptacles 22, 21 are detached from the nozzle heads 10, 12 so that the surfaces of the nozzle heads 10, 12 and the ink receiving member 21 can be cleaned by a blade 27B mounted on a slide 27 to be reciprocated on a rod 27R.
Here, if an air discharging pump 25 comprising means 20 for discharging a waste ink is driven for applying a negative pressure in an air-liquid separating chamber 30P, the bubble-like waste ink stored in the ink receptacle 22 via a discharging pipe 23 is vacuumed into the air-liquid separating chamber 30P so as to be separated into a gas and a liquid. The separated liquid (waste ink) is collected in a waste ink bottle 26 according to the drive of a waste ink discharging pump 24 provided in the discharging pipe 23. Therefore, the liquid (waste ink) can be collected without scattering the waste ink or fouling the surroundings.
As shown in FIG. 2A, the conventional air-liquid separating chamber 30P comprises an upper lid (upper structure) 32P having a separation promoting member 40P comprising an air-liquid introducing inlet 33, a gas discharging outlet 37 and a baffle plate for prohibiting the flow of a bubble-like waste ink. The upper lid 32P is mounted on a main body 31P shown in FIG. 2B for providing the air-liquid separating chamber 30P as shown in FIGS. 2C, 3 and 4, with a configuration wherein the inside of the main body 31P is separated in two by the baffle plate.
The air-liquid mixture Qia discharged from the air-liquid discharging outlet 33 enters the left room shown in FIG. 3 so as to flow downward. It is separated into the gas and the liquid at the lower end part of the baffle plate 40P. The separated gas (air) flows upward toward an air-liquid discharging outlet port 37 as well as the heavy ink Qi is discharged from an ink discharging outlet port 35.
In order to provide the above-mentioned configuration in the conventional air-liquid separating chamber 30P, the main body 31P and the baffle plate (40P) need to be increased in height. However, similar to the case of other devices, the above-mentioned ink jet printer is strongly required to have a smaller size, and thus there is a limitation in increasing in height. Besides, in order to achieve a higher image quality printing, it is intolerable to have a slight amount of an ink mixed in a gas discharged to the outside as well as scattering of the ink.
These problems are not limited to the above-mentioned ink jet printer, but similar problems are involved in the other devices, which require collection of an air-liquid mixture. Moreover, in some applications, a gas remained in a collected liquid can never be allowed. In this case, achievement of a small size while improving the separation efficiency is required.